package org.summerframework.core.util;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class IpUtil {
    private static final String UNKNOWN = "unknown";
    private static final String LOCAL_ADDRESS = "127.0.0.1";
    private static final String separator = ",";
    private static String DEFAULT_LOCAL_ADDRESS;

    public static String getIpAddr(HttpServletRequest request) {
        String ipAddress = null;
        ipAddress = request.getHeader("x-forwarded-for");

        if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader("Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getRemoteAddr();
            if (LOCAL_ADDRESS.equals(ipAddress) || !CheckUtil.checkReg("((25[0-5]|2[0-4]\\d|((1\\d{2})|([1-9]?\\d)))\\.){3}(25[0-5]|2[0-4]\\d|((1\\d{2})|([1-9]?\\d)))", ipAddress)) {
                if (DEFAULT_LOCAL_ADDRESS != null) {
                    ipAddress = DEFAULT_LOCAL_ADDRESS;
                } else {
                    // 根据网卡取本机配置的IP
                    InetAddress inet = null;
                    try {
                        inet = InetAddress.getLocalHost();
                    } catch (UnknownHostException e) {
                        e.printStackTrace();
                    }

                    if (inet != null) {
                        ipAddress = inet.getHostAddress();
                        DEFAULT_LOCAL_ADDRESS = ipAddress;
                    }
                }
            }
        }

        // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
        // "***.***.***.***".length()
        if (ipAddress != null && ipAddress.length() > 15) {
            // = 15
            if (ipAddress.indexOf(separator) > 0) {
                ipAddress = ipAddress.substring(0, ipAddress.indexOf(separator));
            }
        }

        return ipAddress;
    }
}
